There are a number of techniques that have been used to measure the electrophoretic mobility of soft samples such as capillary zone electrophoresis, membrane confined steady state electrophoresis, the Tiselius apparatus, and electrophoretic light scattering, including Laser Doppler Electrophoresis (LDE). LDE measures mobility of particles by measuring particle motion under the application of an external electric field. Referring to FIG. 1, the particles 16 are dispersed in a buffer 14 and electrodes 24, 26 are immersed into the sample. The field is applied and at very high buffer conductivities and degradation of the sample can occur at the electrode surface. For protein samples it is also believed that the oxidation-reduction reaction at the electrode surface ionizes bonds within the protein structure creating aggregates 18 which then both adhere to the electrode surface and are dispersed into the rest of the sample. The volumes typically associated with LDE can also be problematic due to high sample cost and the iterative nature of LDE measurement optimization.